Cars don't exactly offer a huge spectrum of emotional communication. The horn, at absolute most, can say only one of five things: double beep ("Hello"), single beep ("Excuse me, the light is now green"), longer single beep ("I said the light is green. I will stab you in the heart with a screwdriver if you don't move this second, you twat"), novelty Dukes of Hazzard Dixie horn ("I'm an obnoxious person and a selfish lover"), and an unbroken beep lasting for upwards of two minutes ("I have collapsed at the wheel and died").

One thing they really can't say is "sorry". Last week, US magazine Pacific Standard asked why cars don't come fitted with a "horn-honk" for apologies. The argument was a good one: with a high-pressured, high-speed activity such as driving, we are far more likely to misread honest mistakes as acts of aggression, and the ability to tell other drivers that you're incompetent rather than rude might cut cases of road rage dramatically.

As it stands, saying sorry with a traditional horn is hopeless. It is just too loud and crass. If you hit the horn after accidentally cutting someone up, for example – no matter how contritely you do it – it sounds as if you are blaming the other driver. Or, worse, that you are extravagantly declaring victory over them, like some kind of insane post-apocalyptic Mad Max gang member.

Lights aren't much use, either. A quick headlight-flash is certainly more polite than a horn, but realistically it is hard to discern whether it means "No, after you" or "I know where you live". If a "sorry" signal were going to be introduced, it would need to be brand new and exclusively for apologising.

But what form could it take? A sad trombone noise? Too sarcastic. A recording of the driver saying sorry out loud? No good if they're a mumbler. A glowing red light that mimics a blushing face? That's a sign of weakness. You may as well hold up a placard asking people to take advantage of you.

A sorry signal would be no substitute for real, nuanced human interaction. As technology stands, nothing can possibly be as effective as the current method for in-car apologies: a raised palm, a grimace and the unshakeable fear that the driver you just wronged will follow you home and beat you unconscious on your doorstep.